This invention relates to an improved mounting structure for a deflectable upright mast. More specifically, the invention relates to an improved structure for an outdoor sign or barrier which permits deflection, without damage, of the sign or barrier by wind forces and the like.
There is often need along vehicle roadways and pedestrian pathways for signs and barriers to provide information and mark off limits. Frequently the need is temporary and thus it is very advantageous to have mountings for such signs and barriers which may be readily assembled and disassembled; yet which will not be moved, disturbed, or overturned by wind and/or the weight of rain and snow, or by air currents generated by the movement of vehicles. Also to some extent it is advantageous that such signs and barriers be temporarily deflectable by a direct contact of vehicles and pedestrians and the like without permanent damage.
There have been a number of structures devised to permit signs and posters to be temporarily deflected by wind forces. One such prior structure is shown in French Pat. No. 1,181,967 wherein as essentially single mast signpost is supported on a pair of resilient and foldable base members. Two additional structures are shown in U.S. Pat. No. 3,662,482 where a poster board is supported on two upright members: in one embodiment the uprights are in turn supported on a torsion bar; and in the other embodiment a pair of flexible compression springs are substituted for the upright members. Also, U.S. Pat. No. 4,309,836 shows an adjustable flexible mast, for holding a sign, extending upwardly from a support frame.
However, the prior structures have involved resilient members which must be able to react in each of two opposite directions thereby tending to overwork the resilient members and increase the likelihood of loss through fatigue or overextension. Also, the prior structures do not provide for adjustment of the resilient members to allow compression against mild prevailingwind forces or sloping terrain whereby themast and sign may be adjusted to be upright in the best visible posture. That is to say, the prior art devices will be deflected to some extent by any given wind force and therefore if there is a constant breeze, the sign will be constantly deflected with loss of some visibility.